Clock



FIG. 1 is a front perspective view of a clock showing my new design;

FIG. 2 is a top view of the clock of FIG. 1:

FIG. 3 is a front elevation thereof;

FIG. 4 is a right side elevation thereof;

FIG. 5 is a rear elevation view thereof; and,

FIG. 6 is a left side elevation thereof.

The ornamental design for a clock, as shown and described.